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Two new publications on the Great Ordovician Biodiversification Event

Hot off the presses!  

The Stigall Lab has two new articles published in the Lethaia special issue “Contextualizing the Great Ordovician Biodiversificaiton Event”. This special issue derives from the IGCP 653 opening meeting in Durham in October 2016, and includes papers on many aspects of the GOBE and related topics.  You can access the entire issue online here.

Our lab has two contributions:

Stigall, A.L. 2018. How is biodiversity produced? Examining speciation processes during the Great Ordovician Biodiversification Event. Lethaia, 51 (2), 165-172. https://doi.org/10.1111/let.12232.

–In this paper, I make the case that it is critical to consider biological aspects of speciation, not only aggregate diversity counts, when seeking the causes of diversification events, such as the GOBE.

Trubovitz, S., & Stigall, A.L. 2018. Ecological revolution of Oklahoma’s rhynchonelliform brachiopod fauna during the Great Ordovician Biodiversification Event. Lethaia, 51(2), 277-285. https://doi.org/10.1111/let.12233.

–This is the second half of Sarah Trubovitz MS thesis, which examines community structure and body size in brachiopod communities across the GOBE in the Simpson Group of Oklahoma.

Bayesian estimation of Ordovician dispersal pathways

 

Today was an exciting day for the lab.  The paper on Ordovician dispersal pathways led by Adriane Lam which incorporates her primary MS thesis research came out. This paper is exciting for several reasons.  First, it’s always great when a student gets their research published! Second, this is the first use of bayesian biogeographic modeling with Paleozoic taxa.  Third, this project represents an evolution beyond a MS thesis project, through collaboration and improvements with additional authors at other institutions, namely Nick Matzke.  I am really so thrilled with how this paper came out.  It is a landmark is methods and has important implications for understanding Ordovician biogeography.  The only downside…Adriane titled it “Dispersal in the Ordovician” as  play on “Pirates of the Carribean” so I can’t get the Pirates theme song out of my head….

Lam, A.R., Stigall, A.L, Matzke, N.J. 2018. Dispersal in the Ordovician: Speciation patterns and paleobiogeographic analyses of brachiopods and trilobites. Palaeogeography, Palaeoclimatology, Palaeoecology, 489: 147-165. Online

Key Points:

  • Bayesian and ML methods were successfully implemented with Ordovician taxa.
  • Founder event speciation was important in the evolution of Paleozoic taxa.
  • Taxa with different larval strategies responded similarly to climate shifts.
  • Ocean currents were key influences on invertebrate dispersal patterns.
  • Results indicate most evolution within clades occurred during climate shifts.

 

Congratulations to our paleo group!

by Alycia Stigall

We had another great showing by our paleontology group at this year’s Department of Geological Sciences annual awards ceremony.

  • Outstanding graduating senior went to Emma Swaninger (Hembree lab)
  • Jenni Carnes (Hembree lab) was recognized at Outstanding TA
  • Ranjeev Epa (Stigall lab) received the Outstanding Graduate Student award
  • I was recognized for Outstanding Faculty Research and Outstanding Faculty Teaching.

It is really an honor to work these talented folks in our paleo group!

Ranjeev successfully defends this thesis!

by Alycia Stigall

Ranjeev passed the final defense of the MS thesis this morning after a lively presentation and discussion of Paleoecology of the Freshwater Ampullariidae from the Late Oligocene Nsungwe Formation of Tanzania. Ranjeev’s thesis describes a new fauna of freshwater gastropods documenting speciation during the initiation of the East African Rift Valley.  It’s a great study of an interesting and significant set of fossils.  Congratulations, Ranjeev!

Nilmani passes her final defense!

by Alycia Stigall

Nilmani is now a Master of Science!  She successfully defended her thesis titled: Hierarchical Spatial Patterns in Paleocommunities of the Late Pennsylvanian Ames Limestone.  Nilmani did a really nice job in her thesis analyzing and interpreting regional vs. local differentiation in contemporanous shallow marine communities across southeastern Ohio.  Congratulations, Nilmani!

 

Review paper on BIMEs: Biotic Immigration Events

Review paper on BIMEs: Biotic Immigration Events

I am extremely pleased to announce the latest paper from my research group.  This is a review of Biotic Immigration Events, which we term BIMEs, in the fossil record focusing on the ecological and evolutionary impacts that fossil large scale invasion events.  We consider examples from the Ordovician through Cenozoic in both marine and terrestrial systems.  The fossil data supports a two-phase diversity cycle in which the immigration event itself reduced speciation and causes faunal homogenization; whereas the subsequent basinal isolation is characterized by increased speculation and diversity accumulation at multiple levels.  We think this model has great potential as a null model to compare and contrast diversification patterns in the fossil record.  Perhaps my favorite part of this study, though, was working with Adriane, Davey, and Jen–former students that are now talented early career paleontologists in their own right.

Stigall, A.L., Bauer, J.E., Lam, A.L., Wright, D.A. 2017. Biotic immigration events, speciation, and the accumulation of biodiversity in deep time. Global and Planetary Change, 148: 242-257. Online

Geological Society of America Reflections

It is difficult to describe this year’s GSA meeting in Denver.  Overall, it was a great meeting, full of the usual pride in my students’ accomplishments, joy of reuniting with colleagues including many Stigall Lab alumni, nervousness about my own talks, and thrill of learning about the newest developments in the science of paleontology.  But I will always remember this meeting for the Paleontological Society banquet.

bear

The Stigall lab was busy presenting cutting-edge science on a wide variety of topics. Current MS students Ranjeev Epa and Nilmani Perera gave excellent poster presentations about Oligocene freshwater gastropods from Tanzania and Pennsylvanian marine community ecology of Ohio, respectively.  Recent alumnus Sarah Trubovitz gave a talk about her MS work on Ordovician brachiopod paleoecology, and I spoke about the importance of alternating dispersal and vicariance regimes in biodiversity accumulation.

ranjeev nilmani
We had a great Stig*Allstars (=name my alumni gave themselves) dinner to kick off the meeting.  Getting together with this talented group of former students turned colleagues is always a highlight.  They are doing such amazing work as PhD students and early career scientists. I’m so very proud of them and excited to see where their careers will go.

img_6525 img_6530

This year’s GSA, however, was really special as I was awarded the Charles Schuchert Award for Excellence and Promise in Paleontology from the Paleontological Society.  This was the 45th time the Schuchert Award has been presented.  It was only the 5th time that a woman received the award, and the first time a woman with children was the recipient.  After receiving the award from the Paleontological Society president, Steven Holland, I was honored to be able to give a short acceptance speech to the nearly 400 paleontologists gathered at our annual banquet.  I focused my remarks on the challenges to women and minorities in paleontology alongside the standard series of thank you’s.  This the first time that increasing participation has been addressed specifically in an award speech, and I felt both very compelled and nervous about making these comments.  I am very glad that I did!  Continuing to engage in conversations about women and minority challenges are very important for continued progress in our (or any) discipline.

Stigall Schuchert Speech schuchert

The full text of my speech is below, and it will eventually be published in the Journal of Paleontology.

RESPONSE BY ALYCIA L. STIGALL
For the Charles Schuchert Award, 25 September 2016

Thank you, Bruce, for your generous words. I deeply thank the Paleontological Society for recognizing me with this honor. I truly am very grateful and humbled to be selected as the 2016 Schuchert Award recipient. As a brachiopod worker from Cincinnati, the Charles Schuchert award holds special significance to me. I am also deeply honored to now be included among the prestigious set of 44 prior awardees. It is particularly gratifying as I am only the fifth woman to receive this award, and first woman who was a mother at the time of the award.

I am extremely thankful to be a paleontologist today. Paleontology is becoming an ever more inclusive and collaborative science. As I look out from this podium, I see a wonderful diversity of paleontologists –diversity of scientific approaches, diversity of focal taxa, diversity of gender, diversity of ethnicities and nationalities. Our diversity makes our discipline stronger.

However, barriers to full and equitable participation in science for women and minorities remain considerable. Implicit bias, higher expectations, under recognition, harassment, and isolation remain substantial concerns. As a society and as individuals, we are taking positive steps to increase dialog, foster support groups, promote awareness, and tackle our own inherent biases. Like all women who continue in science, I have overcome such challenges in my career, but tonight I stand here excited and optimistic that the future of our discipline will be one of ever increasing inclusion.

I would not be here tonight without the support of my family, colleagues, and friends, and I’d like to take the rest of my time to recognize some of them. First I must thank my parents. As teachers, they have been steadfast in their support of my love for learning, rocks, and fossils. When I was a child, they took me to national parks in 47 states, they accompanied me to rock and mineral shows, gave me a copy of a 1962 Golden Guide to Fossils, and allowed me to disappear into the nearby stream to hunt fossils for hours at a time. Those early experiences surrounded by loving support gave me the confidence to truly pursue my goals and dreams.

As an undergraduate at the Ohio State University, I had the amazing good fortune to learn morphology and systematics (with a Swedish accent) from Stig Bergström who taught me the importance of deeply understanding a clade and of adopting promising new approaches during one’s career. Loren Babcock instilled in me a sense of boundless enthusiasm for prehistoric creatures. And Bill Ausich taught me how to be an excellent scientific citizen, the importance of loving your clade, and above all pursing excellence in science. I am so thankful for the enduring support of Bill and Stig, which has been instrumental in my development as a scientist.

I graduated from OSU with a career goal to resolve early arthropod phylogeny–but quickly reoriented my research interests to studying the complex impacts of biogeography and ecological change on macroevolutionary patterns. In graduate school at the University of Kansas, I worked on phyllocarid crustacean phylogenetics of my master’s thesis, but rapid realized the limitations of working on uncommon fossils for my research agenda. So I shifted my focal taxon to rhynchonelliform brachiopods, and I haven’t look back. (Although I greatly enjoy working with conchostracans from time to time) Brachiopods are truly awesome.

Throughout graduate school, Bruce Lieberman was amazing mentor in every dimension of the word. He taught me how to construct a project, how to succeed in publications, and the importance of perseverance. Even beyond graduate school, Bruce’s promotion of my career has been immeasurable, and I thank him very deeply.

In my twelve years at Ohio University, I have been privileged to work with very supportive colleagues in our Geological Sciences department, an immensely talented set of paleontologists sprinkled across campus, and fantastic collaborators in the Patton College of Education. Working in a department with the master’s as our terminal degree offering, I’ve had the distinct pleasure of working very closely with each of my graduate students. My greatest scientific joy has been mentoring and encouraging my students—now numbering 13—as they develop from scientific novices to confident, accomplished scientists conducting research publishable in top journals. I am very proud of them, and certainly wouldn’t be standing here before you tonight without this exceptional group of students turned collaborators, many of whom are here to support me tonight.

Although I did not know many women paleontologist as a student, I have benefitted greatly from knowing and learning from many amazing women as a professional. In particular Margaret Fraiser, Sandy Carlson, Brenda Hunda, Lisa Park Boush, Dena Smith, and Peg Yaccobucci have been co-conspirators and role models in various ways. I thank the women who trailblazed in the cohorts ahead of mine, and I am greatly inspired by the women in the junior cohorts behind me.

I also thank my colleagues outside of this room. My approach to science has been considerably broadened and enriched by collaborations with modern biogeographers and ecologists as well my international colleagues with whom I’ve studied fossils on all seven continents.

Finally, and most importantly, I must thank my husband, Dan Hembree, who has been my partner in this journey since our first day of graduate school at Kansas. He has always believed in me, even when I did not. His friendship, laughter, encouragement, and discussions have made my science and my life so much richer, and I can’t imagine either without out him. Lastly, our children Max and Josie make everything awesome. It has been invigorating to re-explore the wonders of fossils through their young eyes.

Thank you again, to the members and Council of Paleontological Society for this recognition. I will strive to fulfill the promise inherent in this award and serve our community well in the years to come.

Eochonetes revision published

The final section of Jennifer Bauer’s MS thesis research, a substantial phylogenetic and morphometric analysis of the Late Ordovician brachiopod genera Eochonetes and Thaerodonta has (finally) been formally published in the Journal of Paleontology.

Bauer, J.E. & Stigall, A.L. 2016. A combined morphometric and phylogenetic revision of the Late Ordovician brachiopod genera Eochonetes and Thaerodonta. Journal of Paleontology, 90 (5): 888-909. Online

Cliff notes version: most of the species previously referred to either genus belong within Eochonetes, Thaerodonta is not a valid genus, and some of the previously referred species don’t belong to this clade at all.  Bonus fun: Jen named some new species including one for her amazing grandmothers and another for a character in her favorite book series.

I’m really very proud of Jen for her really excellent work on this project. I am also very pleased that we could clear up some of the confusing nomenclature around Cincinnati fossils.  The species variably known as Thaerodonta clarksvillensis and Eochonetes clarksvillensis is now definitively Eochonetes clarksvillensis.

clarky

*until someone else revises the genus at a later time

New Paleontology Minor at OHIO!

by Alycia Stigall

I am so pleased to announce our new paleontology minor at Ohio University!

New Paleontology Minor Offers Fossil and Earth History Experience – Ohio University | College of Arts & Sciences

Starting this fall semester, a new Paleontology Minor is available to Ohio University undergraduates interested in fossils and ancient life. The Paleontology Minor provides a broad overview of the discipline of paleontology for students interested in developing additional training in fossil identification and interpretation, sedimentary systems, and the history of …

Species-level diversity curve for Middle Ordovician Laurentian brachiopods published in GEOLOGY

Congratulations to alumnus Sarah Trubovitz on the publication of her MS thesis research in GEOLOGY!   **clicking this link bypasses the paywall, so click here!

Also, this is the first official publication of IGCP 653: Onset of the Great Ordovician Biodiversification Event. Our project is off to a great start!

 

Synchronous diversification of Laurentian and Baltic rhynchonelliform brachiopods: Implications for regional versus global triggers of the Great Ordovician Biodiversification Event

The profound global impact of marine radiations during the Great Ordovician Biodiversification Event (GOBE) is widely appreciated; however, diversification varied among paleocontinents and these individual trajectories are less understood. Here we present a new species-level diversity curve for rhynchonelliform brachiopods from midcontinental Laurentia based on bed-by-bed analysis of the Simpson Group of Oklahoma (USA).